DE1508168A1 - Process for wind refining pig iron - Google Patents

Description

B. WEHR, H. SEILER H. STAND M AKN

DIP LO M- I NQENIEURE L Dl PUO M-I N Q EN I EUR

BiRLiN-QRUNiWALD- ¹ PATENTANWÄLTE nürnbbrq β LYNARSTR A S S E 1 ESSENWEINSTR 4-O TELEPHONE: 87 (57 28 and B7 87 81 TELEPHONE: 26Ο35 and 20047 TELEQRAM ADDRESSEILWEHRPATENT TELEGRAM ADDRESS; STANDING PATENT BANK ACCOUNT: BANK ACCOUNTS: BERUNER BANK A.-Q., BERLIN-HALENSEE DEUTSCHE BANK A.Q. NUREMBERG No. 1434 DEP.-KASSE 30. GIRO ACCOUNT NO. 97 236 VOLKSBANK FÜRTH'BAY .. ACCOUNT NO. 4824 POST CHECK ACCOUNT ι BERLIN-WiSOSS POST CHECK ACCOUNT: NUREMBERG C7P 81

27

rg, February 12, 1962

FOEG-ES DE IA PEOYIDENCE, Societe Anonyme, Maronienne-au-Pont

(Belgium)

it process for wind freshening Eoheisen "

The invention relates to improvements in the method for wind refining Eoheisen, in particular phosphorus-containing Eoheisen »

It is known that Eoheisen is wind-freshened in the V / eise to carry out the oxidizing gas, namely technical pure oxygen, from above and / or into the metal bath contained in a converter with a closed bottom by means of a_ water-cooled lance is blown in, which is not immersed in the bath »

In the known methods, the loop-forming Additions to the bath either directly in flour or coarse v-enigsr Pieces or fresh gas supplied through their suspension.

I.Iit this VurfaLron was.: G zvar mö.: Lic: .., iyjilLio von i: emerkenswcrtcn -.- i _c j2noca & iton: ju c rhi .. ". · Th ^ ift-.di -.- er.; :: ■■ ;; -:

909841/06 /; 1

COPY BAD ORIGINAL

1501168

in certain cases from one melt to another unequal-w moderate properties of the metal produced

It is also known today that fresh from Eoheisen by blowing oxygen in one around its longitudinal axis performing rotating hairdressing furnace »With these well-known Processes are used for dephosphorization and for KüJUang serving gas strikes generally in pieces before and during of blowing added »This procedure has the MaeJrfceil, cause the refractory furnace lining to wear out very quickly.

The aim of the present invention is to provide a method which allows the above-mentioned, inherent disadvantage of those known methods to be avoided, namely unevenness

,,, lining

the properties of the metal produced and excessive / the ",

In the case of the process which is the subject of the discovery.

the Bohgisen in two phases by means of one

risked
0-ases / that from the top of the bath into a symmetrical converter with a full bottom that can be rotated about its] jängsaohse

will
blown in ??; The method is characterized in that the converter remains in an upright position at rest during the first prischarge phase and the oxidizing gas is blown into the bath by means of a non-immersed lance, the greater ϊβϋ of the slag forming required for this phase in the form of pieces and / or introduced by iulver into the metal bath and this first fresh phase with an intermediate

901041/0641

Purification stops when the carbon content of the Bath is between $ 1.7 and $ 0.7, and that during the • Second fresh phase of the converter in horizontal or against the horizontal alignment slightly inclined position lowered and, after it has been set in rotation about its longitudinal axis, the oxidizing gas is blown into the bath by means of a second, non-immersed lance, "with the greater part of the slag former required for this phase in Io rm of Pieces and / or powder in the metal bath, preferably is introduced into the bath zone hit by the oxidizing gas

The process of the subject of the invention has the great • advantage that it ensures an efficient agitation of the bath during the whole period of treatment C.

As a result of the constant stirring of the bath, this is physico-chemical Equilibrium between the metal and the material lacquer was practically established during the whole treatment as with Martin trial. It follows that the final properties of the steel produced can be controlled with much greater accuracy than with the known methods.

ο Mach an advantageous embodiment of the invention

oe> procedure one begins to carry out the Prischvorganges ^ so that the converter with a batch of pig iron and a

σ> measured amount of lump lime to be charged. The converter will

- * brought into a vertical position, the blow lance in his neck let in vertically and blown the oxygen into the bath, in which powdery slag-forming substances are suspended

-4-ORIGINALINSPECTED

150t168

are - like lime with added iron oxide, for example in the form of mill scale or ores.

According to a further "modification of the procedure, instead of of lime powder in the axis of the oxygen jet slag-forming substances of coarser grain size are introduced. the Oxygen lance then advantageously contains a central channel, which is independent of the oxygen channel, through which these granular channels Slagging agent directed into the axis of the oxygen jet will.

After all, excessive foaming may be necessary to avoid the slag of the first phase, and to this

For the purpose, this can be made sufficiently fluid from the start * by placing a flame made of oxygen and a gaseous fuel with a high calorific value on the slag that does not penetrate the bathroom, so that they only use the Slag heated enargic.

The fuel and the oxygen for the combustion can be supplied through a special lance or through the main blowing lance will. In this case, it is equipped with auxiliary channels arranged for this purpose.

The flame can be advantageous with the help of smaller, diagonally against the The surface of the bath is formed by directed gas jets.

These agents allow the amount of foaming to be controlled by regulation to regulate the burner output. .

909841/0641

■ ■ ■ ■ -5-

By lowering this power, the heating of the slag becomes smaller and its foaming is stronger. The opposite effect is obtained by increasing the burner output. Adding iron oxide also makes the slag more liquid and less foaming *

If the intention is the pig iron very quickly freed from phosphorus to ', it is important to increase the activity of the slag by sodium carbonate, eg ₀ with empty "briquetted form introduces into it ,,..

This: Briquettes are put through a chute in the converter like this brought in that they just finished melted in the blink of an eye are, in which the blowing of the first phase is stopped.

According to another modification of the invention, the sodium carbonate is used introduced in the lorm that it was also marked with eggs pulverized lime is suspended in the oxygen jet. This Soda supplement combats the foaming of the slag and this can even be suppressed completely when added to the bathroom The amount of soda added with the lime is sufficient «It is therefore possible to by suitable regulation of the soda feeder the foaming of the slag

_o automatically to get to the desired extent «to

~ ^ Preferably 3 to 10 kg of sodium carbonate per l'onne des

Q ₅ .... treated pig iron either in briquette form or in the form of

^ fabric

- * added powder suspended in sour / jet «

The crute ¥ erfahreniii, 3c is ended as soon as the carbon content ('-SjO Tacles auf'.'inen z ^T ./l^chon 1 _t 7 ^ una ö <,? / =, Vorsi ^ -; swo.ti., c

BATH ORIGINAL -G

is decreased in value between $ 1.2 and $ 0.9. This point in time is determined as a function of the amount of oxygen blown into the bath

measured; will. . "'■" ■ "-.

A simple chemical calculation, the result of which is corrected according to the results obtained in the previous processes, permits the very easy determination of the total amount of oxygen to be introduced into the bath during the course of the first phase is to the carbon content for example in a range to bring between 1> 7 $ and Gf # F $

However, since one is not exactly the relevant Sntphosphorungs- and Knowing the cooling flow rates, one cannot with absolute knowledge with the mere knowledge of the amount of oxygen blown in with an absolute amount. accurately determine the carbon content after blowing a predetermined amount of acid off is reached ..

If at the end of the first phase you want someone between narrower boundaries To achieve lying carbon content, it is necessary to have a Carbon content a little before the presumed end the first. Phase.

f "? It is advantageous to proceed as follows:

^ Taking into account the previous processes, the

⁰ ^ to reduce the carbon content s, for example, down to Ij r _t * ~ * the amount of oxygen to be introduced into the bath is calculated »,

The "BIr.sen is interrupted, the eanze is withdrawn, uiiu luicii Lowering the converter v / ird c-ine EetallacliöyipiObe ontno.::i:ien.

BAD LOCATION

A rapid carbon determination is made on this protein (e.g. with the carbometer) completed, as well as a phosphorus determination » if you have a quantitative spectrograph ".

If one knows the remaining carbon and phosphorus content of the bath, then "one can easily determine by calculation or by means of tables the amount of oxygen that still has to be blown into the bath in order to bring the metal to the prescribed G-contents of carbon and phosphorus. If the carbon content determined on the sample is higher than 1 _f 5 - 6, the converter is erected in the vertical position, the lance is reinserted and a sufficient amount of oxygen (which is recorded) is blown in to bring the carbon content to approximately 1.2% , whereupon the blowing is stopped The converter is then lowered, the bath is deslagged and the second treatment phase is started

^ • If, on the other hand, the carbon content of the sample is below $ 1.5, then it works after the bath has also been deslagged, immediately proceed to the second phase.

To carry out the second phase, the converter is lowered, whereby

_<x> it is inclined slightly against the horizontal direction so that its

*> »Longitudinal axis against the horizontal one preferably between

15 below and 25 above the same inclination

The converter is now rotating around its longitudinal axis at a speed between 20 and 50 revolutions per minute set in rotation. Then the second lance is inserted into the pear.

out and blown into the bath the amount of oxygen still to be introduced to terminate the Prischens. In the oxygen jet the slag-forming substances such as lime with or without soda and iron oxide additives are advantageously suspended in powder form.

It should be noted that the pri-fright ions are all the better the greater the speed of rotation of the converter ο

According to an advantageous form of the method, the slag formers introduced in the form of grains, which by a device fed by a mechanical centrifuge .in the from Oxygen beam struck metal bath zone are thrown. .

As in the first phase, you can slag in the soda briquettes so that it is made more active if one wants to obtain an extremely low final phosphorus content »

It has been found advantageous to regulate the inclination of the converter and that of the lance so that the oxygen jet penetrates deeply into the bath, preferably between half and three quarters of its total duration, from the beginning of the second phase near the ^is -onverterhalSo The deep penetration of the oxygen jet into the bath and the eotation of the converter accelerate the freshening reactions very much. This deep penetration of the oxygen jet into the bath near the converter neck also offers the great advantage of throwing out the oxidized metal. / to reduce the wall and the loden of the converter and therefore to reduce the corrosion and wear of the refractory lining. COPY ~ ' ^] ~

During most of the second blowing phase, the end will be the lance against the horizontal by an angle between 35 ° and 90 ° inclined, -whose preferred value was close to 45 °

Subject * of the invention is avoided, the escaping from the bathroom Burn carbon oxide in the converter so that the refractory lining is not subjected to excessive thermal stress which caused rapid wear and tear in the existing processes

In the method according to the invention by omitting loss resulting from carbon dioxide combustion in the pear in terms of heat utilization compared to the known processes is minimal · In any case, this loss is largely due to the significant Offsets savings resulting from better maintenance of the refractory lining

To the end of the prisch process with all desirable accuracy To be able to master, -will in the last moments preferably during the last quarter of the total duration of the second phase, which reduces oxygen supply, either by reducing the blowing pressure or by using a lance of smaller usable width »In addition, according to" the invention ^ During this period, the lance is advantageously inclined in such a way that the oxygen blows onto the surface of the bath, around the ° to enable inclusions scattered in the mass to be separated _ ^ licheno For this purpose, the lance is turned against the horizontal by one between 15 and 45 angle., preferably at an angle of 20, inclined

copy - ¹⁰ -

- Io -

The blowing is stopped as soon as the registering flow meter indicates that the intended amount of oxygen is in the bath has been introduced * At this moment the rotation is started of the converter stopped and the lance withdrawn. It will then a metal sample is taken to complete the composition to check a rapid analysis seminar. If necessary, you take a short complementary blow to complete the freshness. The purging and pouring out of the metal will be according to the procedures continuously used in Thomas steelworks completed *

To apply the method according to the present invention, a symmetrical converter is advantageously used, the inner wall of which is expanded from the bottom to the hood in the form of a cone of rotation, the angle of the generator with the longitudinal axis of the converter being between Lö ° and S5 ° and preferably close to 18 °, Oil conical hood closes against the neck * whereby the angle at the tip of this cone is between 70 ° and 13 & ^Ö 'i preferably close to 9 @ ° *.

The converter is supported by a fit or cradle with the help of raceways that lie in planes perpendicular to the converter length * A motor carried by the cradle can cause the converter to rotate around its longitudinal axis _{if desired ω.} the

to the cradle itself is equipped with pegs resting in fixed bearings oo

** see * their common axis of rotation perpendicular to the converter—

"*** longitudinal axis is arranged 1st, so that the converter

Cfy Ic

4 ^ load-bearing cradle can be tilted so that it is in senreente or in a lying position "

As an example, two processes for the production of steel with a carbon content of 0.100 according to the invention are described below Process described without the invention being limited thereto.

example 1

To carry out the hairdressing process, a symmetrical one is used Converter with full bottom used, which is rotated around its longitudinal axis by means of a rotary drive mounted on the cradle can be rotated; the converter rests in the cradle on raceways, which are arranged in planes perpendicular to the converter axis. This cradle can have two coaxial pins in the Kind of a conventional converter.

At the start of the process, the converter is charged with 28 t of pig iron, approximately J t of scrap iron and 500 kg of lump lime.

The pig iron introduced contains 3.5 $ C, 1.9 $ P, o, 4 # Si and o, $ 300 mn. After erecting the pear that is in its. Cradle blocked is lowered, the vertical lance is lowered and oxygen in an amount of 100 Nnr / mln (normal cubic meters per minute at O degrees Celsius and 760 mm of mercury) and below one

effective pressure of 12 kg / cm. During this Blasens grained lime is continuously introduced into the converter at an allowance of 19okg / min. A vibrating distributor is used for this and a feed line is used which throws the lime into the bath zone on which the oxygen jet impinges. The bubbles will after about 14 min. set after I.385 only oxygen blown into the bath and 2.64o kg of granulated lime with a content 2.24a kg of effective CaO were introduced. The one by the lance

909841/064 1

- 12 -

1.385 only oxygen of 99.5 $ purity leading bath taking into account the losses in the converter vapors I.315 Nm oxygen. During this first phase carbon burns to form CO and CO "in the ratio of 70 $ CO and 30 $ COg. The lance is now raised and the converter is turned over. Then the phosphorus-rich slag is removed, which contains 23 $ po ^ c ^and 6 $ iron. A scoop sample of the metal is taken for the spectrographic determination of phosphorus and carbon, and the bath temperature is then measured using an immersion thermocouple. It is found that the metal contains 1.2 $ C and $ 0.15 P and its temperature is 1,580 ⁰ C.

Now 2,900 kg of scrap are brought in. The converter will inclined so that its longitudinal axis forms an angle with the horizontal of 20 °, with the neck higher than the ground, and the pear at a speed of 28 revolutions / min, set in rotation. There will be a lance of oxygen through your throat

introduced, the blowing pressure of oxygen being 3 kg / cm and the feed is 4 oN no / min. After about 14 minutes of blowing 580 Nm ^ oxygen and 335 kg are thus incorporated into the bath Granular lime has been introduced. After these 14 minutes the blowing becomes a final composition check and the temperature of the metal interrupted. If necessary if the desired composition is not achieved, blowing will resume for a few seconds,

The endgültige'Zusammensetzung the steel contains o loo $ C, o, o2o $ P, o, loo $ Mn and less than 0.003 $ N at a temperature of ⁰ C. I600

- 13 -

0 9841/06 1 * 1

It should be noted that the pig iron in the course of the prishing has undergone a $ 70 desulphurization and that in pig iron included at $ 0.050. Sulfur passed into the steel with o, ol5 # is.

After finishing the refining process, the lance is withdrawn and the casting is poured into the metal pan through one in the converter neck Attached pouring hole made.

In the steel beam flowing into the pan, 3 ^ 0 kg of fresh molten iron with a manganese content; added from $ 50. The manganese content of the steel is increased to 0.400%.

The slag is retained in the pear for the following process.

The balance of the fresh process described is as follows:

l.ooo! ig pig iron charge, 2 ^ 7 kg of scrap were in the the first phase and 5 kg of very much added in the second phase, which results in a total load of 1 * 35 ° kg. There were 1.220 kg of steel obtained. So the yield of the process was

₌ 9q 5 £ _{β T he} different sections of the just 1.350

described fresh process have the following duration:

09841/0641

Charging with 28 t pig iron "Io min

7 t scrap l / 2t * lime

Blisters in the 1st phase 14 min

Deslagging, spectrographic testing, Temperature measurement,

Loading with 2.9 t scrap Bubbles in <&& p 2, phase

Abehlessenäe exam and. tempera towers ssung

-Io rain 4th min 14th min 5 min 5 min

g in; the pan
Sesame duration of the process 62 min

The same converter as in the X. example is used and a äem srssten. Example of very similar frlsoiiproizess carried out.

4KötKferter _; , tier the liquid slag from the previous

It is finished with 28 t of pig iron, originally 1 t of scrap iron and 2sö kg lump lime toesßhiökt. Bas inforaehte Boheisen ^ contains

ο, 4 ^ Sl.

It wiird seakreöhte the lance lowered and oxygen in the extent of ^f ß loo Sm ^ / win under an effective pressure of 12 at blown "Ber oxygen jet contains in suspension a mixture of lime and pulvensiertem Natriiiinkarbonat in the ratio of

--Z

1.8 kg mixture, per who of the injected oxygen.

Blowing is stopped after 14 minutes, during which time in the bath l4oo -NKi ^ oxygen., - 2,3βο kg lime and l4o kg NatriQm-

carbonate. ■

9D9841 / O6% 1 " ¹⁵ "

The lance is withdrawn, the converter is turned over and the slag is removed. At the end of this first phase, this contains Metal 1,2 # C and o, o8 # P and its temperature is 1.580 C.

Now 2,900 kg of scrap are brought in. The pear rises below the horizontal with the neck lower than the ground inclined.

The pear is set in rotation at a speed of 28 revolutions per minute. An oxygen lance goes through the throat introduced with an inclination of 458 from the horizontal. The oxygen blown into the bath through the lance contains in suspension a mixture of powdered lime and sodium / carbonate in the ratio of 0.58 kg per Nm of the blown Oxygen. The blowing pressure is 6at and the feed is 80 Nm / min. After about 7 minutes of blowing, 580 Nm of oxygen were blown into the bath, and JIo kg of powdered lime and 28 kg Sodium carbonate introduced in powder form. After these 7 min the blowing is stopped for a final check of the composition and temperature of the metal. One finds o, loo $ C, o, ol4 $ P, ο, Ιοο ^ Μη and a nitrogen content below 0.003 $, the temperature being 1,6oo ° C.

After the fresh process has ended, the lance is withdrawn and. the pouring into the metal pan through one in the converter neck Attached pouring hole made. The steel jet flowing into the pan gives> 40 kg of freshly melted iron with a Manganese content of 5o # added. So it becomes the manganese content of steel increased to 0.400 #. The slag is in the pear retained for the subsequent freshening process.

9 0 9841/0641 - Claims -

Claims (11)

Claims 1.) Process for refining pig iron in two phases by means of an oxidizing gas flowing from the top of the bath into a symmetrical converter that can be rotated about its longitudinal axis is blown in with a full bottom, characterized in that the converter is in an upright position during the first fresh phase The position remains at rest and the oxidizing gas is blown into the bath using a non-immersed lance, the greater part of the slag-forming required for this phase Means in the form of pieces and / or powder introduced into the metal bath, and this first fresh phase with a Intermediate deslagging is ended when the carbon content of the bath is between $ 1.7 and $ 0.7, and that during the second fresh phase, the converter is lowered into a horizontal position or a slightly inclined position relative to the horizontal and after it has been set in rotation about its longitudinal axis 'is not the oxidizing gas in the bath by means of a second immersed lance is blown in, the greater part of the ächlackenbildenden Bittel in the form of pieces and / or Powder is preferably introduced into the bath zone hit by the oxidizing gas. 2.) Fresh process according to claim 1, characterized in that that during the first phase on the slag one made of oxygen and a flame generated by a gaseous fuel of high combustion value which does not penetrate the metal is directed, so that it only vigorously heats the slag. 9 0 9841/06 U 1 3.) Fresh process according to claim 1 or 2, characterized in that that the activity of the slag is increased by introducing into it sodium carbonate briquettes made from powdered sodium carbonate and a binder such as metallurgical tar are so composed that they are fully just at the time are melted, in which the blowing is interrupted to detoxify. 4.) Fresh process according to claim 1, characterized by that the foaming of the slag by blowing in the oxygen jet suspended sodium carbonate powder is controlled, wherein the slag foams less, the more sodium carbonate is blown in. 5.) Prischverfahren according to claim j5 or 4, characterized in that that per ton of treated pig iron j5 - Io kg Nattium carbonate are introduced. 6.) Method according to one of claims 1 to.5 * thereby characterized in that during the second phase of the process ο ο Longitudinal axis. Of the converter one between 15 below and 25 receives a slope lying above the horizontal. 7.) Method according to one of claims 1 to 6, characterized in that that during the second phase the speed of rotation of the converter about its longitudinal axis between 2o and 5 ° revolutions per minute. 8.) Method according to one of claims 1 to 7> characterized in that the inclination of the converter and that of the lance 909841/0 6 41 from the beginning of the second phase onwards during one preferably tent lying between half and 3/4 of its total duration be regulated so that the oxygen jet, preferably near the converter neck, penetrates deep into the bath. 9.) Method according to one of .Ansprüche 1 to 8, thereby characterized that in the course of the second phase the lance against the horizontal in a position between 35 ° and 9o, preferably close to 45 °> lying angle is inclined, -wherein the lance inclination is determined so that the blown Oxygen reacts with the metal without burning the carbon dioxide escaping from the bath. Io.) Method according to one of claims 1 to 9, characterized in that during the last moments, preferably during the last quarter of the total duration of the second phase, the oxygen supply either by reducing the blowing pressure or by using a lance with a smaller usable diameter is reduced, and that during this period the lance is inclined so that the oxygen is blown superficially onto the belt, the lance against the horizontal at a position between 15 ° and 45, preferably at 2o ^;; Angle is inclined. 11.) Converter for carrying out the procedure according to one of the Claims 1 to Ip, characterized in that it is a symmetrical Has a vessel, the inner wall of which widens conically from the bottom to the hood, the angle of the cone generating is between Io and 25 relative to the longitudinal axis of the converter and is preferably 18 °; that he had one against his neck 90984 t / 064 1 ~ ⁴ " 1SQ3168 has to be closed conical hood, wherein the apex angle of the cone between Jo ° and -130 ⁰ and is preferably close 9o °; that the converter is carried by a fitting or cradle by means of running tracks arranged in planes perpendicular to the longitudinal axis of the converter, a motor carried by the cradle being able to rotate the converter around its longitudinal axis as desired, and that the cradle is provided with bearing journals resting in fixed bearings whose common axis of rotation is arranged perpendicular to the longitudinal axis of the converter and which enable the converter carried by the cradle to be tilted so that it can be brought into a vertical or lying position. 909841/0641